Smartphone-based immunochemical sensor exploiting peroxidase-like activity of ligand-capped gold nanostars: a proof-of-concept detection of Mycobacterium bovis

Javier Lou-Franco, Yunfeng Zhao, Joost L.D. Neils, Linda Stewart, Karen Rafferty, Christopher Elliott, Cuong Cao*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)
62 Downloads (Pure)

Abstract

Bacterial pathogens represent a safety concern in the food industry, and this is amplified by the lack of sensing devices that can be applied on-site by non-trained personnel. In this study, peroxidase-mimicking activity of gold nanostars was exploited to develop a user-friendly colourimetric sensor. A smartphone was exploited as an image reader and analyser, empowered with a novel App developed in-house. The mobile App was evaluated and compared with a commercial smartphone App for its capability to quantify generated colourimetric signals. A major obstacle found with sensors relying on gold nanozymes is the fact that modification of the surface of gold nanoparticles with biorecognition elements generally lead to a suppression of their nanozyme activity. This drawback was overcome by introducing an autocatalytic growth step, which successfully restored the peroxidase-mimicking activity through generation of new gold nanoseeds acting as catalytic centres. A proof-of-concept using this sensing mechanism was developed targeting Mycobacterium bovis, a zoonotic pathogen primarily found in cattle but that can be transmitted to humans by consumption of contaminated food and cause tuberculosis disease. The resulting smartphone-based immunological sensor has shown promising results with a linear response between 104 – 106 CFU/mL, enabling detection of M. bovis at concentrations as low as 7.2·103 CFU/mL in buffer conditions. It is anticipated that the concept of the developed approach will have applicability in many fields relying on smartphone-based biosensing.

Original languageEnglish
Article number114857
Number of pages10
JournalBiosensors and Bioelectronics
Volume220
Early online date03 Nov 2022
DOIs
Publication statusPublished - 15 Jan 2023

Keywords

  • Gold nanostar
  • Mycobacterium bovis
  • Biosensor
  • Smartphone
  • Food pathogen

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